Sewing machine



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United States Patent The invention relates to a sewing machine,particularly a cloth or work feeding mechanism for a high-speed sewingmachine. The feeding mechanism according to the invention may be appliedto sewing machines with single feed dog as well as with differentialfeed dog, in which one or two feed bars are moved up and down by meansof a lifting rocker and a cam, and, at the same time, oscillatedhorizontally by a feed rocker. The two feed bars ofa differential feedmechanism are arranged parallel to each other, and are operated jointlyby the feed rocker.

It is an object of the present invention to design the cioth feedingmechanism of the above mentioned type of sewing machines in such amanner that the main driving shaft of thefsewing machine can rotate athigher speeds.

A further object of the invention is to adapt the feed mechanism in sucha way that the portions of the feed bars which project out of thelifting rocker will become as short as possible and thus will form ashort lever arm. This is an important feature for sewing heavy and thickfabrics, in order that the feed bars do not deflect under the highthrust created by the presser foot. Furthermore,'the oscillating speedof the lifting rocker can be lower when the projectioning lever arms areshort.

Another object of the invention is to design the feed mechanism assimply as possible in order to avoid the driving mechanism of the feeddogs to be composed of too many moving parts, which might give rise tofailures. With the type of sewing machines with differential feed dog inparticular it is intended to eliminate the complicated means employedgenerally for transmitting the movement from the main driving shaft tothe feed dogs of the sewing machine, which is essential for attaining ahigher working speed of the sewing machine.

A still further object of the present invention as applied to sewingmachines with differential feed mechanism, is

to reduce the length of the diflerential feed bar. 'As a result, thesewing machine can be operated at a greater number of revolutions thanwith machines, the differential feed dog of which is supported by a longbar-and operated by a complicated driving gear. 1

Finally it is an object of the present invention to provide aeloth feedmechanism composed of the least possible number of moving parts, wherebyinertia forces are reduced. 1

According to the invention, a sewing machine with single cloth feed isprovided with a main driving shaft, suitably supported in the machineand adapted to be rotated by the driving gear of the sewing machine, afeed dog adapted to transport the cloth and, for this purpose, to movealong the path of an ellipse, the major axis of which is horizontal, afeed bar rigidly connected to said feed dog, a lifting rocker in whichsaid feed bar is'mounted ata right angle with respect to said maindriving shaft, said feed bar being adapted to shift in said liftingrocker and said feed dog being located directly beside said liftingrocker. Also according to the invention a cam is provided fixed to themain driving shaft 2,782,742 Patented Feb. 26, 1957 and rotatablymounted in said lifting rocker. A swinging head rockshaft is suitablysupported in the sewing machine and parallel to said main driving shaft.A feed rocker is pivotally mounted upon said swinging head rockshaft,said feed bar being pivotally and directly connected to said feedrocker, and means are provided operable by said main driving shaft andadapted to transform said feed rocker into an oscillating swingingmovement about the axis of said swinging head rockshaft.

In a sewing machine with differential feed mechanism according to theinvention there are provided a main driving shaft suitably supported inthe machine and adapted to be rotated by the driving gear of the sewingmachine, a feed dog and a differential feed dog, both being adapted toadvance the cloth to be sewed and each of which being adapted to movealong the path of an ellipse, the major axis of which is locatedhorizontally, a feed bar and a differential feed bar, being mountedparallel to each other and each of them being rigidly connected to therespective feed dog, a cam fixed to said main driving shaft, a liftingrocker in which said cam is rotatably mounted and in which said feed barand said differential feed bar are shiftably mounted and adapted toexecute a shifting motion at a right angle to said main driving shaft,said feed dog and said differential feed dog being located directlybeside said lifting rocker, a swinging head rockshaft suitably supportedby the sewing machine and located parallel to said main driving shaft, afeed rocker pivotally connected to said swinging head rockshaft, saidfeed bar being pivotally and directly connected to said feed rocker,means operated by said main driving shaft and adapted to transform saidfeed rocker into an oscillating swinging movement about the axis of saidswinging head rockshaft, a cross slider shiftablymounted on said feedbar and located close beside said lifting rocker and being rigidly fixedto one end of said differential feed bar, and a lever pivotallyconnected at one end to said lifting rocker and at the other end to saidcross slider and adapted to shift said cross slider to and fro alongsaid feed bar.

Further details may be seen from the accompanying drawings which show,for purposes of illustrating the present invention, several embodimentsin which the invention may take form, it being understood that thedrawings are illustrative of the invention rather than limiting thesame.

'In these drawings:

Fig. 1 is a side view, partly in section, of a single cloth feedmechanism,

Fig. 2 is a top view of the mechanism of Fig. 1,

Fig. 3 is a side view, partly in section, of a mechanism withdifferential feed dog mechanism,

- Fig. 4 is a top view, partly in section, of a mechanism according 'toFig. 3,

Fig. 5 is a side view of a mechanism according to Figs. 3 and 4, shownin the direction of the arrow cm Fig. 3,

Figs. 6 to 9 are side views partly in section of four modified crosssliders for differential cloth feed mecha- 'nism, shown in'the directionof the arrow D in Fig. 4,

and partly sectioned along the line AB in Fig. 4,

Fig. 10 is a vertical sectional view of a portion of a feed bar takenalong the line EF in Fig. 4.

The cloth feed mechanism with single feed dog according to Figs. 1 and 2comprises a feed dog 1 of conventional design, which is attached to afeed bar 2 by means of a screw 34. The feed bar 2, for weight reducingpurposes, is supplied with an inner bore 15 which is open at the end ofthe feed bar opposite to the feed dog 1. The feed bar 2 is shiftablymounted in a bore of a lifting rocker 3 which is adapted to move thefeed bar 2 up and down, Furthermore, a feed rocker 4 imparts ahorizontal oscillating motion to the feed bar 2, the resultant of bothimpulses being a motion of the feed dog 1 along the path of an ellipse.

A main driving shaft 6 suitably supported in the sewing machine carriesa cam 7 whichris adjustable to take a specific angular position on themain driving shaft 6 and which is fixed thereon by a screw 35. Thelifting rocker 3 is mounted on the cam 7, which moves the lifting rocker3 up and down. The feed bar 2 is mounted at right angles to the maindriving shaft 6.

In the sewing machine a swinging head rockshaft 8 is positioned parallelto the main driving shaft 6, and according to the embodiment presentedin Figs. 1 and 2, is rigidly attached to the sewing machine. A hub 13 isrotatably mounted on the swinging head rockshaft 8 and is connected tothe feed rocker 4, which may also be integral with the hub 13. The feedrocker 4 has a slot 36 of the kind represented and designated by 19 inFig. 5. The slot 36 receives one end of the feed bar 2, which ispivotally connected to the feed rocker 4 by means of a bolt 20.

The aforementioned pivotal connection is represented in detail in Fig.10. The articulated end of the hollow bushing 12 penetrates into thebore of the eye 47 of the connecting rod 10 and is fixed therein by ascrew 48 fastened in the bushing 12.

When the main driving shaft 6 is rotated, the feed rocker 4, by means ofcam 9, connecting rod 10, lever 11, and hub 13 executes an oscillatingmotion and transmits it to the feed bar 2.

As a matter of course, the arrangement may also be such that the hub 13is eliminated; In this case the swinging head rockshaft 8 is rotatablysupported in the sewing machine, and the feed rocker 4 and the lever 11are fixed to the swinging head rockshaft 8.

The design of the feed dog 1 of a differential feeding I mechanismaccording to Figs. 3 to 5 is substantially the feed bar 2 is suppliedwith an eye 18, having a bore which partly penetrates into the bore 15of the feed bar 2 and which is adapted to receive the bolt 20. A bushing22 with an internal thread is inserted in the bore 15 of the feed bar 2and is supplied with a curved tangential groove 23, the radius ofcurvature of which is greater than the radius of the bolt 20. Into thebushing 22 is screwed a head screw 21 whose head 37 bears against theface of the feed bar 2. When the screw 21 is fastened, the bushing 22shifts in the bore 15 and the bolt 20 is clamped, the groove 23 therebyexerting a wedging efifect on the bolt 20.

The main driving shaft 6 is adapted to impart an oscillatory movement tothe hub 13 by means of an intermediate mechanism comprising a cam 9, aconnecting rod 10, and a lever 11, which is fixed to the hub 13. Themain driving shaft 6 carries a set collar 38 which is slotted and isclamped to the main driving shaft 6 by means of screws 39. One face ofthe set collar 38 is provided with a dove-tailed groove 40 into whichthe dove-tailed foot 9' of the cam 9 is shiftably located. The cam 9surrounds the main driving shaft 6 with suflicient clearance so that itmay be adjusted eccentrically with respect to the main driving shaft 6.The foot 9' of the cam 9 can be connected to the set collar 38 in adetermined position by means of a screw 41 which clamps together theslot of the set collar 38. For this purpose, the slot of the set collar38 and the clamping screw 41 are arranged in such a way that the axis ofthe clamping screw 41 is situated at right angles to theadjustingdirectron of the foot 9 of the cam 9. Furthermore, in-a bore ofthe set collar 38 a bushing 42 is provided, having, parallel to itsaxis, a fiat portion which is in contact with the face of the foot 9 ofthe cam 9. A screw 43 is provided which penetrates through the bushing42 and is screwed in the set collar 38, thus locating the bushing 42,whereby the flat portion of the bushing 42 is pressed against the faceof the foot 9 of the cam 9, which is fixed thereby in its determinedposition. An arrangement of this kind is shown more clearly in Fig. 5.

The connecting rod 10 is supplied with a slotted eye 44, and is heldtogether by a screw 45 and is articulated to the cam 9. The cam 9 has aspherical outer surface 9". The inner bore of the eye 44 is machinedequally spherical, so that the eye 44 is articulated self-adjusting onthe cam 9.

The lever 11 has a slotted end 46 which is clamped to the hub 13 bymeans of a screw 14. The opposite end of the lever 11 is also formed asa slotted eye 11 in which a bushing 12 is inserted which can be fixed inthe eye 11' by pressing together the lips of the eye 11 by means of ascrew 49. A corresponding embodiment of the last-named connection isrepresented in Fig. 5. The

same as that represented in Figs. 1 and 2. In addition, a differentialfeed dog 16 is provided which is secured to a differential feed bar 17.The latter is arranged parallel to the feed bar 2 and is shiftablysupported in a second bore of an enlarged lifting rocker 300. Thedifferential feed bar 17 is supplied with a bore 17' which is open tothe end of the differential feed bar 17 carrying the differential feeddog 16. The opposite end 17" of the differential feed bar 17 is securedto a cross slider 24 shiftably mounted on the feed bar 2. The crossslider 24 carries a projecting trunnion 25, which bears the eye 50 of alever 23. The opposite end of the lever 23' is formed as an eye 23" inwhich the feed rocker 400 is articulated.

Compared with the feed rocker 4 the feed rocker 400 is enlarged, and hasa wing 26 with a slot 27 parallel to the plane through the axis of theswinging head rockshaft 8 and the axis of the bolt 20. A screw 28 with ahead 28 is provided which can be adjusted and fixed in the slot 27 in apredetermined position. The screw 28 is screwed into a nut 29 having theform of a bushing with a flange 29'. A spacer 30 is inserted between theflange 29' and the wing 26, the eye 23" of the lever 23' being rotatablymounted on the spacer 30.

The differential feed bar 17 executes an oscillating movement proceedingfrom the cam 9 of the main driving shaft 6 and being transmitted to thefeed bar 17 by the intermediate rocking linkage comprising theconnecting rod 10, lever 11, hub 13, feed rocker 400, lever 23 and crossslider 24. The stroke of the aforementioned oscillating motion isadjustable by means of the screw 28 which can be shifted and fixed in adetermined position in the slot 27 of the feed rocker 400. The slot 27takes such a position, that the stroke of the differential feed dog 16can be made equal to, or smaller or larger than that of the feed dog 1.

It is important that the feed bar 2 and the difierential feed bar 17 areguided exactly parallel to each other. In order to avoid any stressdetrimental to the parallel motion of the two feed bars and possiblyoccasioned by the manner of fastening "the end 17" of the differentialfeed bar 17 to the cross slider 24, a special connection is provided forthis purpose, which is represented in detail in the Figs. 6 to 9.

According to the structure set forth in Figs. 6 and 7, one end of thedifferential feed bar 17 is supplied with flat surfaces situatedparallel to the connecting plane of the axis of the feed bar 2 and thatof the differential feed bar 17. The cross slider 24 has a slot 31extending in thedirection of the aforesaid connecting plane and intowhich the end 17" of the differential feed bar 17 penetrates. The widthof the slot 31 corresponds to the distance of the aforementionedparallel surfaces of the differential feed bar 17. The two lips 24 and24" of the slotted portion of the cross slider 24 are connected togetherby one or more screws 32, to clamp the end 17" of the differential feedbar 17.

The screw 32 according to the embodiment of Fig. 7 is located outsidethe end 17". According to Fig. 6 it penetrates through a bore of the end17".

The embodiment according to Fig. 8 provides a cross slider 24 with ahere into which the end of the differential feed bar 17 penetrates. Theend 170 of substantially circular cross section is supplied with a flatportion 51 against which presses a screw 33 fastened to the cross slider24.

An embodiment according to Fig. 9 provides a differential feed bar 17with an end 1700 of circular cross section which seats in acorresponding bore of cross slider 24. A slot 52 is supplied in thecross slider 24 extending up to the bore 1700. The jaws 53 and 54 formedby the slot 52 are penetrated by one or more screws 55 adapted to clampthe end 1700.

What I claim is:

1. In a high speed sewing machine a cloth feeding mechanism comprising amain driving shaft supported in the machine and adapted to be rotated bya driving means of the sewing machine, a feed dog adapted to feed thecloth to be sewed and to move along the path of an ellipse the majoraxis of which is horizontal, a feed bar rigidly connected to said feeddog, a lifting rocker in which said feed bar is mounted and is adaptedto shift in a direction at right angles to said main driving shaft, saidfeed dog being provided directly adjacent said lifting rocker, a camfixed to said main driving shaft and rotatably mounted in and entirelysurrounded by said lifting rocker, a swinging head rockshaft supportedin the sewing machine parallel to said main driving shaft, a feed rockerpivotally mounted on said swinging head rockshaft, said feed bar beingpivotally connected to said feed rocker, and means operated by said maindriving shaft to place said feed rocker under an oscillating swingingmotion around an axis of said swinging head rockshaft, said meansincluding a cam mounted on and connected to the main driving shaft, aconnecting rod of which one end is pivotally connected to saidlast-mentioned cam, a hub rotatably mounted on the stationary swinginghead rockshaft and the feed rocker being secured thereto, and a leversecured to said hub with one end thereof pivotally connected to theother end of the connecting rod, the swinging head rockshaft beingpivotally mounted in the sewing machine, and the feed rocker and thelever operating said feed rocker being secured to said swinging headrockshaft.

2. In a high speed sewing machine a cloth feeding mechanism comprising amain driving shaft supported in the machine and adapted to be rotated bya driving means of the sewing machine, a feed dog and a differentialfeed dog both adapted to feed the cloth to be worked and each of whichis adapted to move along the path of an ellipse the major axis of whichis horizontal, a feed bar and a differential feed bar mounted parallelto each other and each of which is rigidly connected to the respectivefeed dog, a cam fixed to said main driving shaft, a lifting rockerentirely surrounding the cam and in which said cam is pivotally mountedand in which said feed bar and said differential feed bar are shiftablymounted to execute a shifting motion, said feed dog and saiddifferential feed dog being provided directly adjacent said liftingrocker, a swinging head rockshaft supported in the sewing machine andarranged parallel to said main driving shaft, a feed rocker pivotallymounted on said swinging head rockshaft, said feed bar being pivotallyconnected directly to said feed rocker, means operated by said maindriving shaft to impart an oscillating swinging motion to said feedrocker around the axis of said swinging head rockshaft, a cross slidershiftably mounted on said feed bar adjacent said lifting rocker andrigidly fixed to one end of said differential feed bar, and a leverlinked to said feed rocker at one end thereof and at the other end tosaid cross slider and adapted to shift said cross slider to and froalong said feed bar, a connecting rod one end of which is pivotallyconnected to said cam, a hub rotatably mounted upon the stationaryswinging head rockshaft and to which the feed rocker is secured, and alever secured to said hub one end of which is pivotally connected to theother end of the connecting rod.

3. In a high speed sewing machine a cloth feeding mechanism comprising amain driving shaft supported in the machine and adapted to be rotated bya driving means of thesewing machine, a feed dog and a differential feeddog both adapted to feed the cloth to be worked and each of which isadapted to move along the path of an ellipse the major axis of which ishorizontal, a feed bar and a differential feed bar mounted parallel toeach other and each of which is rigidly connected to the respective feeddog, a cam fixed to said main driving shaft, a lifting rocker entirelysurrounding the cam and in which said cam is pivotally mounted and inwhich said feed bar and said differential feed bar are shiftably mountedto execute a shifting motion, said feed dog and said differential feeddog being provided directly adjacent said lifting rocker, a swinginghead rockshaft supported in the sewing machine and arranged parallel tosaid main driving shaft, a feed rocker pivotally mounted on saidswinging head rockshaft, said feed bar being pivotally connecteddirectly to said feed rocker, means operated by said main driving shaftto impart an oscillating swinging motion to said feed rocker around theaxis of said swinging head rockshaft, a cross slider shiftably mountedon said feed bar adjacent said lifting rocker and rigidly fixed to oneend of said differential feed bar, and a lever linked to said feedrocker at one end thereof and at the other end to said cross slider andadapted to shift said cross slider to and fro along said feed bar, thefeed rocker being provided with a wing member which is provided with aslot, a nut and a screw with a head, the screw penetrating said slot andbeing adjustable and fixable therein, the nut being shaped as a bushingwith a flange, a spacer inserted between the flange and said wing, saidlever being articulated relative to said cross slider and to said feedrocker, and the one end of said lever being shaped as an eye surroundingthe spacer.

4. In a high speed sewing machine a cloth feeding mechanism comprising amain driving shaft supported in the machine and adapted to be rotated bya driving means of the sewing machine, a feed dog and a differentialfeed dog both adapted to feed the cloth to be worked and each of whichis adapted to move along the path of an ellipse the major axis of whichis horizontal, a feed bar and a differential feed bar mounted parallelto each other and each of which is rigidly connected to the respectivefeed dog, a cam fixed to said main driving shaft, a lifting rockerentirely surrounding the cam and in which said cam is pivotally mountedand in which said feed bar and said differential feed bar are shiftablymounted to execute a shifting motion, said feed dog and saiddifferential feed dog being provided directly adjacent said liftingrocker, a swinging head rockshaft supported in the sewing machine andarranged parallel to said main driving shaft, a feed rocker pivotallymounted on said swinging head rockshaft, said feed bar being pivotallyconnected directly to said feed rocker, means operated by said maindriving shaft to impart an oscillating swinging motion to said feedrocker around the axis of said swinging head-rockshaft, a cross slidershiftably mounted on said feed bar adjacent said lifting rocker andrigidly fixed to one end of said differential feed bar, and a leverlinked to said feed rocker at one end thereof and at the other end tosaid cross slider and adapted to shift said cross slider to and froalong said feed bar, one end of the differential feed bar being providedwith surfaces parallel to the connection plane of the axis of the feedbar and of the differential feed bar, the cross slider being providedwith a slot at the point in which said cross slider is contacted by saiddifferential feed bar, and said slot being located in the direction ofsaid connecting plane and having a width corresponding to the distanceof said parallel surfaces of said differential feed bar, the two lips ofsaid cross slider formed by said slot being connected together by ascrew to permit said screw and said lips to clamp the end of saiddifieren- 802,098 Free Oct. 17, 1905 tial feed bar. 1,109,635 MoffattSept. 1, 1914 1,148,446 De Voe July 27, 1915 References Cited in thefile of this patent 2,102,202 Ebert Dec. 14, 1937 UNITED STATES, PATENTS5 77 M nn A g- 1 1945 572,682 Merl-0w Dec. 8, 1896 2'546939 Breul 95684,266 Klemm Oct. 8, 1901

